Given 'struct dev_pagemap' spans both data pages and metadata pages be
careful to consult the altmap if present to delineate metadata. In fact
the pfn_first() helper already identifies the first valid data pfn, so
export that helper for other code paths via pgmap_pfn_valid().
Other usage of get_dev_pagemap() are not a concern because those are
operating on known data pfns having been looked up by get_user_pages().
I.e. metadata pfns are never user mapped.
Fixes: 6100e34b2526 ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
include/linux/memremap.h | 6 ++++++
mm/memory-failure.c | 6 ++++++
mm/memremap.c | 15 +++++++++++++++
3 files changed, 27 insertions(+)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 79c49e7f5c30..f5b464daeeca 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -137,6 +137,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap);
+bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn);
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
@@ -165,6 +166,11 @@ static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
return NULL;
}
+static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
+{
+ return false;
+}
+
static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
{
return 0;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 78b173c7190c..541569cb4a99 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1308,6 +1308,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
*/
put_page(page);
+ /* device metadata space is not recoverable */
+ if (!pgmap_pfn_valid(pgmap, pfn)) {
+ rc = -ENXIO;
+ goto out;
+ }
+
/*
* Prevent the inode from being freed while we are interrogating
* the address_space, typically this would be handled by
diff --git a/mm/memremap.c b/mm/memremap.c
index 16b2fb482da1..2455bac89506 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -80,6 +80,21 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id)
return pfn + vmem_altmap_offset(pgmap_altmap(pgmap));
}
+bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
+{
+ int i;
+
+ for (i = 0; i < pgmap->nr_range; i++) {
+ struct range *range = &pgmap->ranges[i];
+
+ if (pfn >= PHYS_PFN(range->start) &&
+ pfn <= PHYS_PFN(range->end))
+ return pfn >= pfn_first(pgmap, i);
+ }
+
+ return false;
+}
+
static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id)
{
const struct range *range = &pgmap->ranges[range_id];
